Fabrication and electro-optic properties of a MWCNT driven novel electroluminescent lamp

We present a novel, cost-effective and facile technique, wherein multi-walled carbon nanotubes (CNTs) were used to transform a photoluminescent material to exhibit stable and efficient electroluminescence (EL) at low voltages. As a case study, a commercially available ZnS:Cu phosphor (P-22G having a quantum yield of 65 ± 5%) was combined with a very low (~0.01 wt%) concentration of CNTs dispersed in ethanol and its alternating current driven electroluminescence (AC-EL) is demonstrated. The role of CNTs has been understood as a local electric field enhancer and facilitator in the hot carrier injection inside the ZnS crystal to produce EL in the hybrid material. The mechanism of EL is discussed using an internal field emission model, intra-CNT impact excitation and the recombination of electrons and holes through the impurity states.